Process of manufacturing contact-pieces between first and second conductors.



UNITED STATES PATE T OFFICE.

WILI-IELM BOEHM, OF BERLIN, GERMANY.

PROCESS OF MANUFACTURING CONTACT-PIECES BETWEEN FIRST AND SECOND CLASSCONDUCTORS.

SPECIFICATION forming part Of Letters Patent No. 695,600, dated March18, 1902. Application filed February 26, 1900. Serial No- 6,561. (Nospecimens.)

To all whom it may concern:

Be it known that LWILHELM BoEHM,chemist,a subject of the German Emperor,residing at 74 Ratheno werstrasse, in the city of Berlin, Kingdom ofPrussia, and German Empire, have invented a certain new and usefulProcess of Obtaininga Conducting Union Between First and Second ClassConductors, of which the following is a specification.

This invention has reference to the manufacture of conductingcontact-pieces from suitable first and second class conductors, and itis intended to obviate the difficulties hitherto presented in theobtainment of a durable contact between first and second classconductors. The attempts made heretofore to obtain this object havefailed to produce the desired results. .Heretofore second-classconductors themselves were used for this purp0se,which in some instanceswere mixed with first-class conductors, so as to arrive at a goodconductibility of the contacts. The employment of second-classconductors is in itself not to be regarded as novel, both as such and insolution. Such application of these substances may be easily inferredfrom their employment as cements in the manufacture of incandescentgas-light, where the supporting platinum Wire Was attached in this wayin the earthy Auer mantle.

The processes heretofore in use showed the disadvantage that thecontacts produced thereby failed to withstand the extremes of heat andsoon became loose or broke or melted away. By my invention I havesucceeded to produce contact-pieces of great durability.

In carrying out my invention I also use second-class conductors as abase, and particularly those oxids which are employed in theincandescent bodyitself-such as oxide of magnesium, aluminium,zirconium, thorium, and cerium; but I proceed in this manner: I subjectthose oxids and their equivalents to'a very powerful heat, such asproduced by a Fletcher gas-furnace or the like or by means of theelectric are, respectively, the electric furnace. I am therebyen abledto soincrease the heat that the originally fritted or molten mass .istransformed into the condition of vapors, according to the strength ofthe heating-current. The mass,which has become condensed by subjectingit to a powerful heat in the manner just described, is allowed to cooland ground to a fine powder,which by the aid of a suitable organic orinorganic combiningagent may be attached at points of connection of theconducting-bodies and is finally dried and burned. By means of thistreatment at a most intense heat the molecules of the substance undertreatment are brought as close as possible to each other, so that theaction goes far beyond a mere fusion, but the porosity of the substanceis overcome and the specific gravity of the material is considerablyincreased. The researches of Moissan have shown the possibility ofextending this action of an increase in the specific gravity and adecrease of porosity, which has beenvknown to some extent for oxid ofmagnesium, to all oxids of metals of the earth and of the alkaline earthgroups. By the application of these facts to the manufacture ofcontact-pieces I am enabled to entirely dispense with the use offirst-class conductors in the manufacture of such contacts and toovercome the possibility of a subsequent shrinkage and fusion of thelight-giving body, which is most likely to occur atthe points ofconnection.

As proof for the dependence of the quality of the contact upon thedegree of heat to'which it was previously subjected, I may mention thatthose oxids which were first fused in the electric furnace wereconsiderably superior in durability to those which were only heated inthe oxygen or hydrogen-oxygen blast.

Provided the heat is increased so as to cause the vaporization of theoxids subjected to this treatment, it is possible to entirely avoid thetedious grinding of the masses, fritted or molten by previous heating,it being only necessary to collect the vapors. The powder thus obtainedmay be first purified by any suitable means and is then made'intocontact-pieces of any form desired, which may be in the form of a pasteor cement or in the form of small rods or tubes or assume any othersuitable shape. In applying these they are preferablyplaced over theends of the incandescent bodies and of the conductors. The joint-sproduced by the cementing or the insertion of tubes may be furtherstrengthened by heating them in the electric are, thus producing fusionbetween themcandescent heating or resistance body and the cement orconductor. By this means the possibility of melting contacts will beentirely eliminated. For currents of but lower intensity the fritting ormelting of the substances will be found sufficient for the formation ofa suitable cement, while higher intensities will generally require theuse of the vaporized product.

It is understood that in employing secondclass conductors I may useoxide, as well as suitable salts-such as the Wolframates, silicates,titanates, or niobates.

It is evident that by my improved process a novel technical effect ofgreat importance is produced.

\Vhat I claim, and desire to secure by Letters Patent of the UnitedStates, is

l. A process for producing a conducting union between first and secondclass conductors by first condensing and overcoming the porosity ofsecond-class conductors serving as contact-pieces by the fritting ormelting action of a powerful heating agent, finely dividing the productafter fusion, subsequently forming it into bodies of any desired shape,and inserting such highly-condensed bodies between the joints.

2. A process for producing a conducting union between first and secondclass conductors by subjecting a material to a melting action ofsuitable duration by means of a powerful heating agent collecting thevapors produced and forming rods, tubes and other bodies therefrom andfinally applying such bodies to the joints, substantially as described.

In Witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

W ILI-IELM B OEHM.

